The following invention relates generally to instrumentalities which are adapted to reduce glare from unwanted light sources that adversely affects viewability of a cathode ray tube. In addition, the device reduces the affinity for such a tube to attract dust on its surface by electrostatic attraction. Moreover, the device restricts visual access to the CRT.
Television sets, computer monitors, oscilloscopes or the like frequently rely upon luminescence of a target screen which is then excited by an electron gun producing a visual image on the screen. Since the envelope of the cathode ray tube relies in part on electrical stimulation, an electrostatic bias exists on the display surface of the screen. As a result, the exterior surface of such a screen displays an affinity for dust.
In addition, because the efficiency of a CRT relies upon the electrical discharge that exists when the screen is stimulated, brightness of the screen can be degraded by other light sources and reflection from brighter light which manifests a form of glare on the screen, all of which creates eye strain. To the extent possible, one tends to divert strong light from direct contact with the screen when it is being viewed in order to provide maximum contrast.
Once such a screen has been sufficiently "tuned" such that it is relatively dust-free and ambient light has been controlled, the clarity of the depiction on the screen will have been enhanced. Sometimes, however, this is undesirable since confidential or sensitive material may be displayed on the screen which is not to be viewed by passers-by.
To date, no known instrumentality exists which has addressed all of these needs and yet provides an attractive display upon which indicia or some form of advertising can be displayed.